Celestial navigation glossary
Ecliptic
The Sun’s yearly path among the stars, tilted 23.44° to the celestial equator; it crosses the equator going north at Aries.
Where the course teaches it
Aries and SHA on the celestial sphere, in the module Latitude from Polaris. Find your latitude at twilight from the Pole Star, with the Polaris tables.
Taught alongside it
- First point of Aries (♈)
- The reference point among the stars; a star’s GHA is GHA Aries plus its SHA.
- Sidereal hour angle (SHA)
- A star’s angle west of Aries; nearly constant, listed on the daily pages.
- Polaris
- The pole star, within a degree of the celestial pole: its altitude is close to your latitude.